LOL. Based on the title I thought OP was leaning his bike on the HVAC condenser.....
OP, Just use some old t-shirts or towels cut to size as protectors, and use some bungees, or something similar to keep bike from swinging around. Allen is the BSO of racks....

bso?

BSO (Bycycle Shaped Object) is a derisive term used to describe those things sold in department stores, online, and other big box outlets that to the untrained eye appear to be bikes. In your case I guess it should be RSO...

You still don't want to hang a carbon bike on the back of a car supported by the top tube. The side load on that tube is not going to do the carbon any favors.

I bought it used for $20 and it has worked so far. I got my money’s wirth out if it. 😆

Anyone with experience with a Saris Freedom spare tire bike rack?
There is one near me that looks to be in almost new condition.
The bike sits on trays instead of hanging.
I also found a Yakima receiver mount where the bike hangs by the top tube. It is also in excellent condition.

Do not hang a CF bike by the top tump on a bike carrier. Don’t clamp any CF tube either except maybe the seat post. Disregard if you want to buy a new bike.

The Saris should be fine.

It isn’t exactly delicate.

I found a like new Yakima hitch mount 2 bike carrier that I will probably buy.

Neither was the CF sailboat boom that I broke at the FW Boat Club when it hit a shroud under load. Only cost me about $5k.

The sidewalls of CF tubes are not that strong and are susceptible to side load impacts.

But, your bike and your money.

I just got around to doing something about it.
Alcohol wipes worked very well. Thanks for the tip.

I bought a used Saris T-Rax rack. It hangs the bike but it will do for now. I don’t take the bike far.
It has some carriers I haven’t figured out yet.
It does fit the receiver on my jeep and just clears the spare tire without needing an extension.
This is beefier than I expected.